H. T. Yi

Mechanism of the Switchable Photovoltaic Effect in Ferroelectric BiFeO3

IO N The ferroelectric photovoltaic (FPV) effect—a photocurrent is created in ferroelectric materials by ultraviolet (UV) light illumination and its direction depends upon ferroelectric polarization—has received considerable attention as a promising alternative to conventional photonic and photovoltaic devices. However, the main drawback of this intriguing effect is that only a tiny photocurrent is generated in typical large-bandgap and highly-insulating ferroelectric materials such as LiNbO 3 . [ 1 , 2 ]

Ultrafast carrier dynamics and radiative recombination in multiferroic BiFeO3

We report a comprehensive study of ultrafast carrier dynamics in single crystals of multiferroic BiFeO3. Using degenerate femtosecond optical pump-probe spectroscopy, we find that the photoexcited electrons relax to the conduction band minimum through electron-phonon coupling with a ∼1 ps time constant that does not significantly change across the antiferromagnetic transition. Electrons subsequently leave the conduction band and primarily decay via radiative recombination on a nanosecond timescale, as supported by photoluminescence measurements. We find that despite the coexisting ferroelectric and antiferromagnetic orders in BiFeO3, its intrinsic nature results in carrier relaxation similar to that observed in bulk semiconductors.

Vacuum Lamination Approach to Fabrication of High-Performance Single-Crystal Organic Field-Effect Transistors

A novel vacuum lamination approach to fabrication of high-performance single-crystal organic field-effect transistors has been developed. The non-destructive nature of this method allows a direct comparison of field-effect mobilities achieved with various gate dielectrics using the same single-crystal sample. The method also allows gating delicate systems, such as n -type crystals and SAM-coated surfaces, without perturbation.

3:1 magnetization plateau and suppression of ferroelectric polarization in an Ising chain multiferroic

Ferroelectric Ising chain magnet

Spin-state crossover in multiferroic Ca3Co2-xMnxO6

{\text{Ca}}_{3}{\text{Co}}_{2\ensuremath{-}x}{\text{Mn}}_{x}{\text{O}}_{6}

Charge carrier coherence and Hall effect in organic semiconductors

(x\ensuremath{\simeq}0.96)

Manifestation of magnetic quantum fluctuations in the dielectric properties of a multiferroic

was studied in magnetic fields of up to 33 T. Magnetization and neutron-scattering measurements reveal successive metamagnetic transitions from the zero-field

Observation of new magnetic ground state in frustrated quantum antiferromagnet spin-liquid system Cs2CuCl4

\ensuremath{\uparrow}\ensuremath{\uparrow}\ensuremath{\downarrow}\ensuremath{\downarrow}

Insulating interlocked ferroelectric and structural antiphase domain walls in multiferroic YMnO3

spin configuration to the